A 22-year-old woman jogging though a secluded track in Karori has managed to fight off a sex attacker with the help of a resident who intervened after hearing her screams.

Police are hunting a man who attacked the woman from behind after she jogged past him at about 8.40pm yesterday on the Old Karori Walkway, a bushy track between Curtis St and Whitehead Rd.

The attacker pulled the woman to the ground and as she fought him off her screams brought a nearby resident rushing to her aid.

As her helper came close the attacker fled the scene and was last seen running south along Curtis S ttowards Appleton Park.

The victim was taken to hospital with moderate injuries but has since been released and is now at home recovering.

Both the victim and the resident who came to her aid were praised by police for their valour.

"It is apparent this is a sexually motivated attack and the victim did a great job fighting the offender off. If not for the timely intervention of the resident the outcome could have been far worse for her," Detective Senior Sergeant John van den Heuvel said.

He said the nature of the attack suggested it was sexually motivated. He would not elaborate on the nature of the woman's injuries but said they were in relation to her physical altercation with her attacker, and she had managed to escape sexual assault by putting up a fight.

Police have examined the scene and would be completing interviews with the victim and the resident who ran to her aid tomorrow.

In the meantime, police urged anyone who saw a man loitering or acting strangely around the walkway recently to contact them.

The offender is described as a male believed to be in his 20s, about 180cm tall with tanned skin, a muscular build, short hair and spoke with a kiwi accent. He was wearing a grey coloured top and possibly board shorts.

Police believed the attacker may also have come away with injuries as a result of his victim fighting back, such as scratches.